JP2000067266A - Raster image display method and editing method, and computer-aided graphic processing system using the same - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a computer-aided graphic processing system capable of confirming the height of a raster image and the sense of unevenness in a two-dimensional display. SOLUTION: When editing a raster image by operation from a mouse 104 and a keyboard 105, a color corresponding to the uneven shape is calculated based on a value of the raster image, a light source is defined in a three-dimensional space, and a light source is defined. Based on the light source and the value of the raster image, the specular reflection component and the diffuse reflection component of the concavo-convex shape are calculated, the calculated color, the specular reflection component and the diffuse reflection component are combined, and the combined concavo-convex shape is calculated. A central computer 101 for displaying a raster image on the display device 107 in real time is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method of displaying a raster image in a computer-aided graphic processing system, and more particularly to a CAD (computer-aided drawing and design),
The present invention relates to display of uneven shapes in a CAM (computer-assisted manufacturing) and CG (computer graphics) system.

[0002]

2. Description of the Related Art Conventionally, in a CG (computer graphics) system or the like, a texture such as a color is defined for a three-dimensional solid shape defined by an equation (Bezier, B-spline, NURBS, etc.), and further a three-dimensional texture is defined. The process of assigning the position of the light source in, calculating the shadow when the three-dimensional shape is illuminated by the light source, and calculating a more realistic appearance is called rendering. Is the ray tracing method,
Although the scan line method and the like can be cited, these rendering processes are computationally time consuming because it is necessary to determine the front and back of a three-dimensional object and to calculate the intersection of a surface and a ray.

[0003] At this time, a method of expressing a subtle unevenness in the three-dimensional shape by attaching a two-dimensional raster image (bump map) in which the unevenness is defined by the value to the three-dimensional shape is applied. There has been a technique called bump mapping or displacement mapping. Details of these methods are described in "Technical Guide CG Standard Textbook" published by the Image Information Education Promotion Association.

[0004] Here, an operation of performing bump mapping or displacement mapping by pasting on a three-dimensional shape will be described. FIG. 5 is a flowchart showing a conventional operation at the time of performing bump mapping or displacement mapping. In this operation, assuming that a three-dimensional shape has already been defined, it is necessary to edit and confirm a desired irregular shape definition raster image. Is what you do.

First, the raster image definition raster image 2
A dimension is defined (S200), and a two-dimensional raster image is confirmed (S201). Here, when defining a two-dimensional raster image defining the concavo-convex shape in S200, as a two-dimensional display method in S201, conventionally, a method of displaying a raster image in black and white according to its value is used. (Hereinafter referred to as "black and white shading"), or
When there is a raster image on a plane in a three-dimensional space, and the value of the raster image defines the height of the unevenness on the plane, a display in which the direction of light is defined and shaded with a single color is displayed. (Hereinafter referred to as "shading in a single color").

Here, the former "black and white shading display" is a general method, which is described in the above-mentioned "Technical Guide CG Standard Text Book", and the latter "monochrome shading". The “display” is also a method generally known in the field of CG.
No. 80086, and the like.

After the confirmation of the two-dimensional raster image in S201, a bump map is pasted on a three-dimensional shape (S202), and three-dimensional rendering is performed from a plurality of viewpoints to determine the position and height of the unevenness. Confirm (S2
03). Then, it is determined whether the raster image defined in S200 is a desired one (S204), and S2 is determined.
If the raster image is not what you want in 04,
Returning to 200, the raster image is defined in two dimensions again, and S200 to S204 are repeated. If the raster image becomes the desired one in S204, the process ends.

[0008]

Conventionally, when editing a raster image (bump map) for defining an uneven shape, even when editing a raster image defining an uneven shape for pasting on a plane, the conventional method is not applicable. In the display method of (1), the shape of the defined concavo-convex height is attached to the three-dimensional shape as shown in S202 and S203 in FIG.
It could not be confirmed until it was rendered in dimensions.

In other words, in the conventional two-dimensional display method of “black and white shading display”, the height can be determined by the shading value, but it cannot be seen three-dimensionally. There was a problem that it could not be confirmed.
As an example of this, in the case of editing a raster image as shown in FIG. 6, the "black and white shading display" is displayed as shown in FIG. 7, and it is almost impossible to distinguish between a spherical shape and a conical shape.

Although there is a "shading display with a single color" in which a three-dimensional light source is set and the diffuse reflection component is calculated from the light source and the gradient of the map value, this method uses
Although three-dimensional irregularities can be intuitively recognized by shading, the surface in the same direction has the same shading value, so that there is a problem that the height cannot be confirmed. As an example of this, in the case of editing a raster image as shown in FIG. 6, the “monochrome shading display” shows a display as shown in FIG. Since the portion is also displayed with the same shaded value, the height of the flat portion cannot be confirmed.

[0011] For this reason, conventionally, because of the drawbacks of the two-dimensional display method described above, even when creating a raster image defining a concavo-convex shape to be attached to a plane, the shape of the defined raster image is checked. In order to do so, it has to be pasted on a three-dimensional shape and rendered in three dimensions by a method such as a ray tracing method, which takes time.

Further, in order to check the height of the uneven shape in the three-dimensional rendering, it is necessary to perform the rendering from a plurality of viewpoints and to check the height. Corresponds to S20 in FIG.
It is necessary to perform three-dimensional rendering in Step 3 a plurality of times. For this reason, as shown in FIG. There was such a problem.

[0013]

According to a first aspect of the present invention, there is provided a method of displaying a raster image in a computer-aided graphic processing system.
Calculating a color corresponding to the uneven shape based on the value of the raster image, defining a light source in a three-dimensional space, and calculating a specular reflection component of the uneven shape based on the light source and the value of the raster image. Calculating, based on the values of the light source and the raster image, calculating a diffuse reflection component of the concavo-convex shape, combining the color calculated in each step, a specular reflection component and a diffuse reflection component, Displaying a raster image of a concavo-convex shape in which a specular reflection component and a diffuse reflection component are combined.

A method for displaying a raster image according to a second aspect of the present invention is the method for displaying a raster image in a computer-aided graphic processing system, the method comprising: displaying a raster image between two colors having high saturation based on a value of the raster image. Calculating a color whose hue changes gradually according to the unevenness of the value, defining a light source in a three-dimensional space, and calculating the specular reflection component of the unevenness based on the light source and the value of the raster image And a step of calculating a diffuse reflection component of the concavo-convex shape based on the values of the light source and the raster image, and a step of combining the color calculated in each step, a specular reflection component and a diffuse reflection component, Displaying a raster image having a concavo-convex shape in which a specular reflection component and a diffuse reflection component are combined.

A method for editing a raster image according to a third aspect of the present invention is the method for editing a raster image in a computer-aided graphic processing system, wherein the raster image is generated and edited based on the displayed raster image having an uneven shape. Calculating a color corresponding to the uneven shape based on the value of the raster image;
Defining a light source in a three-dimensional space, calculating the specular reflection component of the uneven shape based on the value of the light source and the raster image, and, based on the value of the light source and the raster image,
Calculating the diffuse reflection component of the concavo-convex shape; combining the color, the specular reflection component and the diffuse reflection component calculated in each step; and calculating the concavo-convex shape in which the color, the specular reflection component and the diffuse reflection component are combined. Displaying a raster image.

A method for editing a raster image according to a fourth aspect of the present invention is a method for editing a raster image in a computer-aided graphic processing system, wherein the raster image is generated and edited based on the displayed raster image having an uneven shape. Calculating, based on the value of the raster image, a color whose hue gradually changes according to the uneven shape of the value of the raster image between two colors having high saturation, and setting a light source in a three-dimensional space. Define, based on the value of the light source and the raster image, the step of calculating the specular reflection component of the uneven shape, based on the light source and the value of the raster image, the step of calculating the diffuse reflection component of the uneven shape, Combining the color, specular reflection component and diffuse reflection component calculated in each step, and combining the color, specular reflection component and diffuse reflection component Those comprising the step of displaying a raster image of the uneven shape.

According to a fifth aspect of the present invention, there is provided a computer-aided graphic processing system comprising: input means for inputting various operation instructions and data; display means for displaying various images; and information input from the input means. Perform image processing,
Control means for displaying the result on the display means, when editing the raster image by operation from the input means, based on the value of the raster image, calculates a color corresponding to the uneven shape, A light source is defined in a three-dimensional space, and a specular reflection component and a diffuse reflection component of the concavo-convex shape are calculated based on the value of the light source and the raster image.
The calculated color, the specular reflection component and the diffuse reflection component are combined, and the combined raster image of the concavo-convex shape is displayed on the display means in real time.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the definition of terms in this embodiment will be described. In this embodiment, a raster image is image data in a narrow sense, but here includes all data that can be defined as a vertical and horizontal array, and includes a case where there is no upper limit or lower limit. I have. Specular reflection is the reflection of light when the light hits the object, in which the light is reflected in the specular direction where the incident angle is equal to the reflection angle. Is the thing. In addition, the diffuse reflection refers to reflection of light incident on an object with the same intensity in all directions in reflection of light when the light hits the object.

FIG. 1 is a block diagram showing a hardware configuration of a system to which a method for displaying a raster image according to the present invention is applied. This system comprises a central computer 101, a main storage device 102, an input / output control device 103,
Mouse 104, keyboard 105, external storage device 106
And a display device 107. Each component is constituted by a computer system 100 connected through a system bus 108 or a similar mechanism.

FIG. 2 is a conceptual diagram of an embodiment of the present invention realized by the computer system 100. On the computer system 100, the command analysis / processing unit 2 shown in FIG.
05 and the graphic information storage area 206 are further constructed, and the command analysis / processing unit 205 and the graphic information storage area 206 are further constructed.
Denotes a display device 203 and a mouse 2 via an input / output mechanism 204.
01 and the keyboard 202.

In FIG. 2, the operator inputs a command from the mouse 201 and / or the keyboard 202, and selects a region to perform the batch processing of the image. Performs definition processing of the image of the shape definition raster image. Then, the defined raster image is stored in a two-dimensional buffer in the graphic information storage area 206, and at the same time, a color (hue, saturation, lightness) calculation unit 2 for converting to a color by a certain equation.
07, the specular reflection component calculation unit 208 for calculating the specular reflection component, and the diffuse reflection component calculation unit 209 for calculating the diffuse reflection component calculate the display color values from the stored raster image values. Is calculated.

The values calculated by the color (hue, saturation, brightness) calculation unit 207, the specular reflection component calculation unit 208, and the diffuse reflection component calculation unit 209 are combined by the synthesis unit 2.
10 selectively synthesizes the two-dimensional buffer for display, and displays it on the display device 203.

Here, an example of calculation by the color (hue, saturation, brightness) calculation unit 207, the specular reflection component calculation unit 208, and the diffuse reflection component calculation unit 209 will be described. First, as an example of a method of converting a raster image into a color in the color (hue, saturation, lightness) calculation unit 207, the maximum value of the raster image is set to “bright green (0,255,0 in RGB expression)”. , Conversely, change the minimum value to “dark blue (RGB
The expression is 0,0,50). Then, the intermediate value of the raster image is obtained by linearly interpolating the RGB values of the color of the maximum value and the minimum value. By associating the two colors with high saturation with the maximum value and the minimum value of the display, it is possible to confirm the change in the height of the unevenness by the change in the hue.

In the calculation of the specular reflection component and the diffuse reflection component in the specular reflection component calculation unit 208 and the diffuse reflection component calculation unit 209, it is assumed that the raster image is on a plane in a three-dimensional space. The calculation is performed by setting the direction of the light source so that light is applied to the plane from a specific direction. As an example of the method of calculating the specular reflection component in the specular reflection component calculation unit 208, there is a method using a phone model. This method is also described in the above-mentioned “Technical Guide CG Standard Textbook”. If the value of the raster image is the value of the height at which the irregularities are formed,
Since the value obtained by differentiating the value is the slope of the unevenness, the specular reflection component and the diffuse reflection component are obtained from the differential value and the direction of light.

Here, if the value of the specular reflection component is Is, Is is obtained by the following equation. Is = Ii Ks cos ⁿ γ where Ii is the intensity of the incident light, Ks is the specular reflectance, γ is the angle between the specular reflection angle and the line of sight, and n is the characteristic of the highlight.
As the value of n is larger, the area of the highlight portion is smaller, and a sharper unevenness is expressed.

Here, the diffuse reflection component calculation unit 20
As an example of the method of calculating the diffuse reflection component in 9, assuming that the value of the diffuse reflection component is Id, Id is obtained by the following equation. Id = Ii Kd cos α where Ii is the intensity of incident light, Kd is the diffuse reflectance, and α is the angle of incidence. The specular reflection component calculation unit 208 and the diffuse reflection component calculation unit 209 calculate the effect of shading when the uneven shape is applied to a plane and light is applied from a certain direction.

Here, the following formula is given as an example of the calculation method of the synthesis in the synthesis unit 210. This is because each of the color (R, G, B) values calculated by the color (hue, saturation, brightness) calculation unit 207 is calculated by the diffuse reflection component calculation unit 2.
09 is multiplied by the value of the diffuse reflection component calculated.
The value of the specular reflection component calculated by the specular reflection component calculation unit 208 is added to each of the RGB components.

If the combined value is I and the color calculated by the color (hue, saturation, lightness) calculator 207 is Ic, in this case, the R, G, and B components of I are as follows: It is obtained by the formula. I = Ic × Id + Is In the above expression, all the values of the color (hue, saturation, lightness) calculation unit 207, the specular reflection component calculation unit 208, and the diffuse reflection component calculation unit 209 are used. However, it is also possible to selectively use and synthesize.

Then, the display of the synthesized result is as shown in FIG. 3 in the case of editing a raster image as shown in FIG. 6. "Height" of dimensional shape
And the "feeling of shape irregularity" can be simultaneously confirmed to a delicate shape.

Next, the operation of editing a raster image in this embodiment will be described. FIG. 4 is a flowchart showing a raster image editing operation according to this embodiment. First, a two-dimensional definition of the concavo-convex shape definition raster image is performed (S100). Then, the above-described color (hue, saturation, lightness) calculation unit 207, the specular reflection component calculation unit 208, and the diffuse reflection component calculation unit 209 are described.
Then, the raster image is confirmed by displaying the two-dimensional raster image processed by the combining unit 210 (S101).

Then, it is determined whether or not the raster image defined in S100 is a desired one (S102).
If it is determined in step S102 that the raster image is not the desired one, the process returns to step S100, where the raster image is defined in two dimensions again, and steps S100 to S102 are repeated.
If the desired raster image is obtained in step 2, the process ends. After the editing of the raster image is completed, a process of pasting a bump map on a three-dimensional shape and performing three-dimensional rendering is performed as in the conventional case.

Since each of the above steps is a process of calculating colors and values by a simple formula from the values of the original raster image, unlike a three-dimensional rendering method that requires a three-dimensional intersection calculation, It is possible to quickly create and display an image obtained by two-dimensionally processing an irregular shape definition raster image without calculating time. Therefore, in the interactive raster image editing operation, it is possible to perform confirmation by defining the unevenness defining raster image in real time, and the editing operation can be performed quickly.

In particular, in the color calculation step, by changing the hue between two colors having high saturation, white and white representing a highlight portion calculated from the specular reflection component can be obtained.
And the change in lightness due to the diffuse reflection component, the change in height expressed by the hue, the highlight white for expressing the three-dimensional unevenness, and the lightness are not confused. It is possible to simultaneously and clearly confirm both the “a” and the “feeling of shape irregularities”.

As described above, in this embodiment, in the raster image display by the two-dimensional display in which the color (hue, saturation, brightness), the specular reflection component and the diffuse reflection component are processed, the raster image is edited. Since the rendering process that takes a long time is performed after the raster image becomes a desired one, the editing time can be reduced. Further, the raster image display by the two-dimensional display can be easily calculated by the above-described formula, and can be displayed in real time, so that the work efficiency can be improved.

In this embodiment, the height of the raster image is expressed by using two colors. However, by using two or more colors, these colors are heightened. The change may be made so that the change of the height can be recognized.

[0036]

As described above, according to the present invention, a color corresponding to the uneven shape is calculated based on the value of a raster image, a light source is defined in a three-dimensional space, and the light source and the raster image are defined. Based on the value, the specular reflection component of the concavo-convex shape is calculated, and based on the value of the light source and the raster image, the diffuse reflection component of the concavo-convex shape is calculated, and the calculated color, specular reflection component and diffuse reflection component are calculated. Are combined and the combined raster image is displayed in a two-dimensional manner without the need to render multiple times using the ray tracing method, etc., when editing the raster image that defines the uneven shape. The effect is that the user can quickly edit both the "height" and the "feeling of shape irregularities" on the editing screen of the That.

Further, based on the value of the raster image,
Between two colors with high saturation, the color whose hue changes gradually according to the uneven shape of the value of the raster image is calculated, so that white, which expresses a highlight portion calculated from the specular reflection component, And the change in lightness due to the diffuse reflection component, the change in height expressed by the hue, the highlight white for expressing the three-dimensional unevenness, and the lightness are not confused. This has the effect that both "a" and "feeling of shape irregularity" can be clearly and simultaneously confirmed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a hardware configuration of a system to which a method for displaying a raster image according to the present invention is applied.

FIG. 2 is a conceptual diagram of an embodiment of the present invention realized by a computer system 100.

FIG. 3 is a diagram showing a display example of a raster image according to the display method of the embodiment (in the case of a raster image as shown in FIG. 6).

FIG. 4 is a flowchart showing a raster image editing operation in the embodiment.

FIG. 5 is a flowchart showing a conventional operation when performing bump mapping or displacement mapping.

FIG. 6 is a diagram illustrating an example of a raster image.

FIG. 7 is a diagram showing a display example by a conventional black-and-white shading display.

FIG. 8 is a diagram showing a display example of a conventional monochromatic shading display.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 computer system 101 central computer (control means) 102 main storage device 103 input / output control device 104 mouse 105 keyboard 106 external storage device 107 display device 108 system bus 201 mouse 202 keyboard 203 display device 204 input / output mechanism 205 command analysis / processing unit 206 Graphic information storage area 207 Calculator for color (hue, saturation, brightness) 208 Calculator for specular reflection component 209 Calculator for diffuse reflection component 210 Synthesis unit

Continued on the front page F term (reference) 5B050 AA06 BA04 DA02 DA04 EA02 EA09 EA16 EA28 FA02 FA06 FA08 FA13 5B080 AA16 BA03 BA07 FA02 GA06 GA14 GA26 GA27

Claims (5)

[Claims] 1. A method for displaying a raster image in a computer-aided graphic processing system, comprising the steps of: calculating a color corresponding to an uneven shape based on a value of the raster image; defining a light source in a three-dimensional space; Based on the light source and the value of the raster image, a step of calculating a specular reflection component of the concavo-convex shape, Based on the light source and the value of the raster image, a step of calculating a diffuse reflection component of the concavo-convex shape, A step of synthesizing the color, the specular reflection component and the diffuse reflection component calculated in each of the steps, and a step of displaying a raster image of an uneven shape in which the color, the specular reflection component and the diffuse reflection component are synthesized. How to display the characteristic raster image. 2. A method for displaying a raster image in a computer-aided graphic processing system, the method comprising: a step of gradually changing a value of the raster image between two colors having high saturation based on the value of the raster image. Calculating a color whose hue changes; defining a light source in a three-dimensional space; calculating a specular reflection component of the concavo-convex shape based on the light source and the value of the raster image; Based on the value of the raster image, the step of calculating the diffuse reflection component of the uneven shape, the step of combining the color calculated in each of the above steps, the specular reflection component and the diffuse reflection component, and the color, the specular reflection component and Displaying a concavo-convex raster image in which diffuse reflection components are combined. 3. A method for editing a raster image in a computer-aided graphic processing system, comprising the steps of: generating and editing a raster image based on a displayed raster image having an uneven shape; Calculating a color corresponding to the irregular shape; defining a light source in a three-dimensional space; and calculating a specular reflection component of the irregular shape based on the light source and the value of the raster image; And calculating a diffuse reflection component of the uneven shape based on the value of the raster image and combining the color, the specular reflection component, and the diffuse reflection component calculated in each of the steps, and the color and the specular reflection. Displaying a concavo-convex raster image in which a component and a diffuse reflection component are combined. How to edit the image. 4. A method of editing a raster image in a computer-aided graphic processing system, comprising the steps of: generating and editing a raster image based on a displayed raster image having an uneven shape; Calculating a color whose hue changes gradually in accordance with the uneven shape of the value of the raster image between two colors having high saturation; defining a light source in a three-dimensional space, the light source and the raster image Based on the value of, the step of calculating the specular reflection component of the concavo-convex shape, Based on the value of the light source and the raster image, the step of calculating the diffuse reflection component of the concavo-convex shape, Combining the color, the specular reflection component, and the diffuse reflection component; and Displaying a star image. 5. An input unit for inputting various operation instructions and data; a display unit for displaying various images; performing image processing based on information input from the input unit; and displaying the result on the display. Control means for displaying on the means, when the raster image is edited by an operation from the input means, based on the value of the raster image, calculates a color corresponding to the concavo-convex shape, Define a light source in a dimensional space, calculate the specular reflection component and diffuse reflection component of the uneven shape based on the value of the light source and the raster image, and calculate the calculated color, specular reflection component and diffuse reflection component. A computer-aided graphic processing system, comprising: synthesizing and displaying a synthesized raster image having an uneven shape on the display means in real time.